Shortcut tree routing and low power scheduling in ZigBee for wireless sensor networks

Abstract

ZigBee is the emerging low-power, low-data rate industrial standard for ad hoc networks based on IEEE 802.15.4 PHY and MAC layers. Due to characteristics such as self-forming, self-healing, reliable communication, network scalability, and easy installation and maintenance, ZigBee is expected to be used in wireless sensor networks for remote monitoring, home control, and industrial automation. Specifically, it is considered as one of candidates for sensor network standards. However, the current ZigBee standard, which was released on Dec, 2004, needs to be improved on its inefficient tree routing and low power scheduling. First, ZigBee tree routing has the problem that the packets follow the tree topology to the destination even if the destination is located nearby, while it can be used in end devices that have limited resources in that it does not require any routing tables to send the packet to the destination. To reduce the routing cost of ZigBee tree routing, we suggest the shortcut tree routing protocol that forwards the packet to the neighbor node if it can reduce the routing cost to the destination. Second, we propose a distributed low power scheduling algorithm for wireless sensor networks as an alternative to the beacon scheduling algorithm that is not standardized yet in spite of being the main algorithm for low power consumption. Considering the sensor network``s characteristic that all sensor nodes report the sensing information to the base station periodically, sensor nodes chooses their active period based on the tree level and sleeps in an inactive period to minimize the power consumption in the proposed algorithm. The proposed schemes make ZigBee more powerful and attractive when ZigBee network protocol is used for the wireless sensor network applications. We expect the ZigBee to become an essential network protocol for the growth of ubiquitous sensor networks.